Yarn package formation



y 26, 1.953 0. A. HITT ET AL YARN PACKAGE FORMATION Filed Oct. 28, 1949INVHVTORS OTHA A. HITT and MESSOUD KIACHIF ATTORNEY.

Patented May 26 1 953 UNITED PAT o 2,639,872 I YARN PAGGKAGE FORMATIONOtha Allen are, Chesterfield County, amnessoud- Kiachif, Richmond, Va.,assignors to-E. I. du Pont de N embers 6; Company, Wilmington,

Del., a corporation or Delaware Application October 28, 1949', Serial N.124,247

4 Claims. 1

This invention relates to the winding of yarns. More particularly, thisinvention is concerned with a method for windingcontinuous filamentyarns'into square shouldered-cylindrical packages. It is furtherconcerned with the production of square shouldered package's suitablefor shipment to distant mills and suitable for direct use on lip-twisterspindles used. to impart a high degree of twist to the yarn In thewinding of yarnszai certain few prede termined wind ratios have. beenmore or less standardized for certain types ofpackages. In spoolinggenerally a very high wind ratio is used, i. e.-, the number of heliceswrapped aroundthe core per' completaback and forth, stroke oilthetraversing guide. This may be in the order of or '30 or even moredepending o'n' the length of the spool, speed of winding, etc. In otherwords, the traverse isslow. However, since the traverse guide isgenerally spaced from 2 to several inches frorn the winding-0n surface,this slow traverse is necessary to get the yarn to fill the spool barrelcompletely.- If the traverse guide is controlled only by a singleprimary cam,

the yarn windings are very hard and bunched at the ends due to th'e lagin reversal; Accordingly, a secondary can! usually causing a shifting ofthe primary travers origin" is also used. While this arrangement-issatisfactory for spool packages of yarn-where spool end flanges arepresent to hold the yarnin place; itis not at all'- satisiactor'y' forwinding onto headlesscorsj such as'cones or cylinders;- such as arewound oh'=a=p'recisi'onor cone winder.

thecase of-theprecision or cone winder the yarn is led-th'rou gliatraverse guide actually riding onorin veryclose proximity-- to the winding-onsurface. In' order to form square shoul= ders withoutmarked-bulging atthe ends the traverse is fast relative totheyarnflwinding speed.- Sincethe traverseguide rides the pack age; therebyeliminating any substantial lag at the ends of the stroke;anacceptablepackage for many-purposes is-produced with-but a single'camfor directing movement" of the traverse guide; This-wind ratio iscommonly of the order'of 4" to 6. However; with this low wind ratiotheyarn stays-*inpla'ce poorly and sucha package cannot berotated athigh speeds onan up tw'ister. Therefore, the yarn is usually takentherefrom while the package is" stationary by drawing it over the end.Then-too this" low Wind ratio 'is very largely confined tb-wiridingontocone cores; the taper of which aids in keeping the-windings inplace.

There is a need in the trade for cylindrical packages of substantialsize of purified,- doped and dried rayon yarn which can be mounteddirectly on up-twister machines vand rotat'e'd -a't' high speed toproduce a high twistyarri;- i; e2,-

crepe twists with lotto turns-per inch. Since, a pound package of lllpdenier yarn-lasts, rotatingcontinuously at 8000-10, 000 R. P. M. for 7or 8 days, provision must be made to prevent the yarn frombeingirreparably soiled. Dirt and dust is twisted into the yarn; ifno'precautions are taken. In copen'd'ingapplicati'on of Paeplow andKiachif Serial No. 9 7,527, filed June 7, 1949,21} paratus is describedfor preventing soiling. In. orderto provide adequate protection of ayarn package, it must be square ended, and the apparatus referred to isused with square-ended packages. Also square ends are required so thatthe conventional type -drop-wire flyer may be used with assurance thatthe guide eye therein will be below the top shoulder. A precision- Windis also necessary. since no supportingflanges can be present but thewind-universally used with use directly on an up-twisterspindle. Anotherobject of this invention is to provide a square ended package permittingthe use of ail-improved winding apparatus: Other objects will beapparent; from the description: that follows.

While not' essential" to an understanding of the invention, thedrawingsp as described below, are presented to illustrate thetrue-cylindrical package formed by the process of the present invention. I

Figure Irrepresents a side'view of aiheadless' core I containing a first2 and" second" 3' lay down; Broken lines 4*" represent the final buildup of the-yarn.

Figure II represents'an"end'view, the numerals identifying identicalelements as in the previous figure.

The objects of this invention are accomplished by preparing in a specialmanner a' squareen'ded cylindrical yarn package that does not distort orslough when rotated-athigh speeds to produce high twist yarns; By squareendedcy lindrical yarn package is 'meant a cylindrical yarn packagehaving auniform thickness from one end to the other. ,The package has notapered sections -eitl ier-at-the ends'or along its length; the planeof-each endsuriace is 'perpen' dicular to the long axisof-the packageand each end is, of course,- circular; the package-'beinga truecylinder. The winding-11saccomplishedby the method of this=inventionWhich'resultsin laying the yarn down at the proper helix'angle and-withproper tensioirupon itso that shoulders orbulged endsareavoiddandso'that'the package is self -supporting' on the headless"core upon which it is wound:

Inorderto produ-c theipackage of thi's inveh ratio in the range of 1250+to 1350+. That is, there are that number of helices of yarn laid downaround the" core for every complete stroke of the traverse guide. Thisrange is operative when a 5% inch stroke is used. A stroke is one backand forth movement of the guide or a complete cycle of the primary cam.The use of this wind ratio determines the helix angle which is lowranging from 12 to 15i1. If a longer or shorter package is to be wound,the same helix angle is maintained, but the ratio may have to be variedsomewhat. The variation is usually not more than Throughout the winding,the traverse guide speed is maintained exactly at a constant ratio tothe primary cam by the use of a gear gainer. To assist in the preventionof bulging shoulders, it is necessary to use a secondary cam ofapproximately inch throw. The cycle of the secondary cam to the primarycam must be maintained at about 1 to 142+. This prevents the lagresulting with the use of a primary cam only and undesirable bulges areavoided. It is further essential that the tension on the yarn in thepackage be accordingly controlled within narrow limits. Tension at thewind-on point should be between 0.17 to 0.38 gram per denier. Thisfigure is based on 100 denier yarn and the range may vary downwardsomewhat for deniers smaller than 100 denier and upward somewhat fordeniers larger than 100 denier.

To determine the tension on the yarn as it is wound onto the package inthe process of this invention, yarn is led from the inside of thetraverse button to a roller well below the winder and returned upwardaround this roller to the package. Tension measurements were taken onthe thread ahead of the button and on the down:

coming thread at the discharge side of the winder button. The lattervalues simulated the tension of the yarn as it is wound on the package.After establishing the relationshipbetween the tension ahead of andafter the Winder button, measurement during control was madeconveniently on the yarn ahead of the button. Constant thread speed wasrequired to maintain the constant tension. During winding the tension ismaintainedconstant at a valuewhich must be between 8 to 14 grams for a100 denier yarn. While this range may be used from package-topackage,the range within agiven package must be held within more narrow limitsto avoid poor package formation. The constant thread speed needed toaccomplish this is attained using mechanical devices as tapered pulleysor properly designed cams. I

By way of example, in winding the 100 denier yarn a square ended packagesatisfactory for use in uptwisting is made using a 5% inch traversestroke with a wind ratio corresponding to 9520 revolutions of the tubefor 741 complete traverse strokes. The wind ratio in every case must bean indeterminate fraction to avoid any possibility of minor ribbonssince these cause bad sloughing during up-twisting operations. It ispreferable for the wind ratio, expressed above, as ranged from 1250+ to1350+ when expressed as a fraction to have a low whole numberdenominator. With this condition, the pattern laid down on the yarnpackage repeats more frequently and a more staple package results.However, if the pattern is repeated before the number of completedtraverse strokes is 25, spiral ridges form at the ends of the package.Accordingly, the numberof traverse strokes before the pattern isrepeated should be from 25 to 741 with the range of 30 to beingpreferred. In demonstrating the critical nature ofthe'wind ratio it wasfound that with a wind ratio of 10, sloughing was so pronounced that theresultant package could not be used at all in uptwisting. With a windratio of 16, cylindrical package formation could not be maintained evenby modifying and increasing the throw of the secondary cam and in spiteof trying all sorts of corrective measures the package always resultedin bulges at the ends which caused repeated breaks when an attempt wasmade to twist therefrom on an lip-twister.

In respect to the acceleration of the primary cam, the wind ratios usedare high enough so that with the ordinary primary cam, bulges result atthe ends of the package. To overcome this, the primary cam isaccelerated at the reversals by about 25% and in addition to this asecondary cam of approximately inch throw is used to reduce the densityof the shoulder. To obtain the desired shoulder density, the cycle ofthe secondary cam to the primary cam must be maintained at about 1 to142+. That is, the secondary cam should make one complete revolution forevery 142+ revolutions of the primary cam. Further, the secondary strokeshould be no less than 2- inch and no more than inch on a 6 inchpackage, for outside that range undesirable shoulder bulges areobtained. This range, of course, will vary somewhat depending upon thelength of the package but for most purposes the range producessatisfactory results, the displacement being adequate. Usually, apackage of about 6 inches is preferred.

In respect to the tension requirements, the yarn being wound on thepackage is normally led to and around a traverse guide at variousangles. This angle may be, for example, of the order of 45 to 100. Dueto this snubbing, the tension on the yarn as measured on the package isgreater than the tension of the yarn as it is led to the traverse guide.In order to obtain a package with equal density on the shoulders and inthe middle or, in fact, throughout the entire package, the tension onthe yarn as it is being fed to the traverse guide must be maintainedbetween 6 to 12 grams for 100 denier yarn with approximately 100angularity around the guide. This tension corresponds to 26 to 38 gramsmeasured on the yarn as it is wound on the package. If a lowerangularity of approximately 45 or less is used, the tension range withinwhich a satisfactory package can be produced is from 6 to 18 grams. Thiscorresponds to tension on the package of 17 to 25 grams. For 100 denieryarns, it is preferred that the tension on the yarn traveling to thetraverse guide be from 8 to 14 grams. Tensions under 8 grams tend toproduce single filament loops. Tensions above 8 grams stretch thefilaments to a common length and are accordingly preferred. Theallowable tensions will, of course, vary roughly depending upon thedenier of the thread. For most operations tension on the yarn travelingto the traverse guide must be maintained between 0.06 to 0.25 gram perdenier with the tension on the yarns at the wind-on point varying from0.17 to 0.38 gram per denier. If the tension is not controlled asdescribed, poor package formation results; sloughing and bulging at theends occur.

7 Of course, in order to maintain the critical limits described above inthe various steps of the process of this invention, the apparatus mustbe Controlled in a precise manner. Thus, for the winding of a headlesshigh wind package having a uniform thickness throughout, it is moreessential that a true running spindle be employed along with aconcentric chuck for the tube, a uniform and low back pressure of about300 to 500 grams, a traverse guide with a sharp V for the thread grooveand a compensated drive to produce constant thread speed. This backpressure is the force exerted on the traverse button by the traverseback of the winder. If this pressure is too high, the package becomeshard and the ends or shoulders are forced out. If too low, the packageis soft and unstable, and, if excessively low, the button loses contactwith the package thereby destroying the precision nature of the wind.

Through this invention, a, package is produced which may be shipped to adistant mill and used directly on up-twister spindles for the productionof crepe twisting yarn. The yarn may have on it a sizing such as is usedin crepe yarns and the doped yarn may be handled directly withelimination for the mills of the steps of doping, drying and spooling.No difficulties are encountered; the package maintains its form throughthe trip and throughout up-twisting. Due to the helix angle of the yarnlay the various courses of yarn maintain their position withoutdistortion even when the package is rotated at spindle speeds of 8000 oreven 10,000 R. P. M. Further advantage of this invention lies in that itis readily adapted to use with the apparatus of Paeplow and Kiachifreferred to above permitting the prevention of the yarn from soilingduring up-twisting. A further advantage of this invention lies in thefact that conventional spool winds are obviated. In such wind-s, thereis insufficient thread helix angle to provide an interlocking pattern.Through the process of this invention a much simpler core can be usedand the difficulties in spool winding are avoided.

Further, by the use of this invention a number of expensive steps in themanufacture of crepe twist yarn are eliminated. As practiced heretofore,skein winding and skein doping followed by drying and then rewinding tospools from which the yarn was thrown were necessary steps. Previously,package sizes were limited to /2 lb. The cost of handling, rewinding andreplacing on the twisters of so many units involved considerable expenseand considerable degradation of the yarn during each and every step ofthe process. By the process of this invention, it is possible to windlarge packages on headless cores and to transfer these directly to theup-twister using apparatus which protects the yarn during uptwistingfrom soilage. Considerable economy in time and equipment and asubstantial increase in output is obtained.

Any departure from the procedure described herein which conforms to theprinciples of the invention is intended to be included within the scopeof the claims below.

We claim:

1. A process for preparing a cylindrical yarn package of uniformthickness which comprises winding a yarn on a headless core by passingit through a traverse guide to said core, said guide having a completestroke of about 5% inches and said guide and said core moving at ratesof speed so that between 12.50+ and 13.50+ helices of 7 yarn are laiddown on said core for every complete stroke of said guide; applying asubstantially constant tension on the said yarn winding on said package,the tension being a value between 0.17 and 0.38 gram per denier;accelerating the traverse guide at the reversals by about 25% andcontinuously displacing the movement of the said guide in smallincrements for a total displacement of about from inch to inchcompleting and reversing each displacement cycle in about 14.2 strokesof said guide.

2. A process for preparing a cylindrical yarn package of uniformthickness which comprises passing a yarn under a tension of 0.06 to 0.25gram per denier to a traverse guide; snubbing said yarn about said guideand passing it therefrom at angle of from 45 to to a headless corewhereby the tension on said yarn winding on said package issubstantially constant being a value between 0.17 to 0.38 gram perdenier; rotating said core and traversing said guide at speeds wherebybetween l2.50+ and 13.50+ helices of yarn are laid down around said corefor every complete stroke of said guide which stroke measures about 5%inches; completing between 25 and '741 complete traverse strokes beforerepeating any helix pattern; and accelerating the traverse guide at thereversals by about 25% and continuously displacing the movement of thesaid guide in small increments for a total displacement of about from3%" to completing and reversing each displacement cycle in about 14.2strokes of said guide.

3. A process for preparing a cylindrical yarn package of uniformthickness which comprises winding a yarn on a headless core by passingit through a traverse guide to said core, said guide having a strokesuch that the lay down on said core has a helix angle of from about 11to 16 degrees; applying a substantially constant tension onthesaidyarnwinding of said package; accelerating the traverse guide atthe reversals by about 25% and continuously displacing the movement ofsaid guide in small increments for a total displacement of about from tocompleting and reversing each displacement cycle in about 14.2

strokes of said guide.

4. A process for preparing a cylindrical yarn package of uniformthickness which comprises winding a yarn on a headless core by passingit through a traverse guide to said core, said guide having a strokesuch that the lay down on said core has a helix angle ranging from about11 to 16 degrees; applying a substantially constant tension on the saidyarn winding of said package; the tension being a value between 0.17 and0.38 gram per denier; accelerating the traverse guide at the reversalsby about 25% and continuously displacing the movement of said guide insmall increments for a total displacement of about to completing andreversing each displacement cycle after about at least 14.2 strokes ofsaid guide.

OTHA ALLEN HITT. MESSOUD KIACI-IIII.

References Cited in the file of this patent UNITED'STA'I'ES PATENTSNumber Name Date 2,205,384 Abbott June 25, 1940 2,304,564 Gladding Dec.8, 1942 2,388,557 Little et a1 Nov. 6, 1945

